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| Titel |
The Passive microwave Neural network Precipitation Retrieval (PNPR) algorithm for AMSU/MHS observations: description and application to European case studies |
| VerfasserIn |
P. Sanò, G. Panegrossi, D. Casella, F. Di Paola, L. Milani, A. Mugnai, M. Petracca, S. Dietrich |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1867-1381
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Measurement Techniques ; 8, no. 2 ; Nr. 8, no. 2 (2015-02-19), S.837-857 |
| Datensatznummer |
250116139
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| Publikation (Nr.) |
 copernicus.org/amt-8-837-2015.pdf |
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| Zusammenfassung |
The purpose of this study is to describe a new algorithm
based on a neural network approach (Passive microwave Neural network
Precipitation Retrieval – PNPR) for precipitation rate estimation from
AMSU/MHS observations, and to provide examples of its performance for
specific case studies over the European/Mediterranean area. The algorithm
optimally exploits the different characteristics of Advanced Microwave
Sounding Unit-A (AMSU-A) and the Microwave Humidity Sounder (MHS) channels,
and their combinations, including the brightness
temperature (TB) differences of the 183.31 channels,
with the goal of having a single neural network for different types of
background surfaces (vegetated land, snow-covered surface, coast and ocean).
The training of the neural network is based on the use of a cloud-radiation
database, built from cloud-resolving model simulations coupled to a
radiative transfer model, representative of the European and Mediterranean
Basin precipitation climatology. The algorithm provides also the phase of
the precipitation and a pixel-based confidence index for the evaluation of
the reliability of the retrieval.
Applied to different weather conditions in Europe, the algorithm shows good
performance both in the identification of precipitation areas and in the
retrieval of precipitation, which is particularly valuable over the extremely
variable environmental and meteorological conditions of the region.
The PNPR is particularly efficient in (1) screening and
retrieval of precipitation over different background surfaces; (2)
identification and retrieval of heavy rain for convective events; and (3)
identification of precipitation over a cold/iced background, with increased
uncertainties affecting light precipitation. In this paper, examples of good
agreement of precipitation pattern and intensity with ground-based data
(radar and rain gauges) are provided for four different case studies. The
algorithm has been developed in order to be easily tailored to new
radiometers as they become available (such as the cross-track scanning Suomi
National Polar-orbiting Partnership (NPP) Advanced Technology Microwave Sounder (ATMS)), and it is suitable for operational use as it is computationally
very efficient. PNPR has been recently extended for applications to the regions of Africa
and the South Atlantic, and an extended validation over these regions
(using 2 yr of data acquired by the Tropical Rainfall Measuring Mission
precipitation radar for comparison) is the subject of a paper in preparation.
The PNPR is currently used operationally within the EUMETSAT Hydrology
Satellite Application Facility (H-SAF) to provide instantaneous
precipitation from passive microwave cross-track scanning radiometers. It
undergoes routinely thorough extensive validation over Europe carried out by
the H-SAF Precipitation Products Validation Team. |
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